did you figuare out the issue, my car has almost the same issues. Once the car runs for 15-20 minutes it starts to hesistate around 2000 RPMs and once you shut it off it runs fine again for a while.
No CODES, no nothing, just an intermittent hesitation when temps are over 85-degrees with A/C on. Problem started shortly after ECM had a Factory Software Upgrade performed. Sometimes when going up hills with slight pressure on the gas pedal, the engine will hesitate (like a bump), or when idling the engine will sound as if the plugs are fouled. When you press the pedal down further, the power comes back strong with no hesitation???!!!! 171K miles with no other issues. This Jeep has been great for 9 years! Any help would be appreciated.